1. Field of the Invention
The invention relates to a polymeric material comprising an interpenetrating network built up from a polymer that can be cross-linked under the influence of radicals and an epoxy resin comprising a cross-linking agent. The invention has for its object the manufacture of new materials especially suited to be used in the electronics industry (electronic materials for short).
2. Description of the Prior Art
A polymeric material of the type mentioned above is known from U.S. Pat. No. 4,468,485. In this patent specification the polymer that can be cross-linked under the influence of radicals is an unsaturated polyester resin. The epoxy resin is of the DGEBA type (diglycidyl ether of Bisphenol-A) and is cross-linked using a polyfunctional amine. For the preparation of an interpenetrating network (IPN) without phase separation the above-mentioned patent specification describes a process in which use is made of microwave radiation of a frequency spectrum so chosen as to effect the cross-linking of the polyester, with the heat released in this process triggering the cross-linking reaction of the epoxy resin. Admittedly, in this manner there is obtained a polymeric material which has one single glass transition temperature (Tg) (in the range of 50.degree.-100.degree. C. depending on the IPN's composition), but the process used is not universally applicable.
Said patent specification thus does not teach the skilled man how, by the proper selection of IPN components, suitable electronic materials can be manufactured.
It is generally known that there is a need to replace the present electronic materials with materials meeting requirements such as
low dielectric constant PA1 low electrical dissipation factor PA1 high Tg PA1 ready processability PA1 low price PA1 high dimensional stability PA1 high solvent resistance
more satisfactorily.
The invention employs IPN technology to obtain materials especially suited to be used in the electronics industry.